Steam boiler



July 24, 1928 v 1,678,235

W. STENDER STEAM BOILER Filed Sept. so. 1924 Patented July 24, 1928.

UNITED STATES 1,678,235 PATENT OFFICE.

WALDEMAR STENDER, OE BERLIN-CHARLOTTENBURG. GERMANY. ASSIGNOR TO SIEMENS-SCHUCKERTWERKE GESELLSCHAFT MIT BESCHRKNKTER HAFTUNG. OF SIEMENSSTADT, NEAR BERLIN, GERMANY, A CORPORATION OF GERMANY.

STEAM BOILER.

Application filed September 30, 1924. Serial No. 740,752, and in Germany September 27. 1923.

My invention relates to improvements in steam boilers and more particularly to boilers fed with water heated in a feed heater and also with cold water.

It is known to overfeed a boiler when steam requirement is small and to store the excess of heated water in a vessel outside the boiler.- In such a system the boiler must be the more overfed and the more heated water must be stored the smaller the difference between the temperature of the feed water and the boiling temperature .of the boiler. The storage vessel must be also made larger. In such cases an economizer or flue gas feed heater is very inconvenient inasmuch as on the one hand it raises the temperature of the feed water and on the other hand requires approximately equal feeding with the fires remaining equal while the hot Water storage vessel demands variable feeding of the boiler. A second storage vessel is thus required forthe feeding water heated in the flue gas feed heater.

According to my invention these drawbacks are avoided by supplying the feed water into the boiler during periods of high steam consumption through an economizer and during periods of loW steam consumption directly; The flow of the heated and the cold water may hereby be regulated by well .known means in dependence from the steam requirement. In order that during periods of high steam consumption the feeding may be eflected with water which has as near as possible the boiling temperature of the boiler water the flow of the Water invention provided in which the excess of water supplied by the economizer during periods of low steanrdemand is stored up in-order to be fed into the boiler as required. It may. however, during periods of very low steam consumption in spite of increased feeding of the boiler with cold water, happen that the steam generation becomes. too strong. In order' to avoid thls, hot boiler water is according to my invention conveyed into the hot water storage vessel besides the water heated in the economizer. This hot boiler water must naturallybe replaced in the boiler by cold water which consumes heat during the heatin to the boiling temperature. The exchange between thc stored hot water and the boiler water may herebv also be regulated in depcmleuce from the steam consumption by means well known per se.

My invention is illustrated in the accour panying drawings in which- Flg. 1 represents diagranunaticall the general lay-out of a system according to niv invention. and I Fig. 2 represents a modification thereof in certain respects to be described hereinafttn'. Referring to' Fig. l. 1 indicates a steam boiler whose generated steam is supplied to the consumers through the pipe The feed water 3 is fed into the boiler either directly by meansof the pump 13 or through the economizer or flue gas feed heaters: by means of the pump 23.

During periods when there is low steam consumption the boiler is fed by the pump 13 only, which is automatically regulated in dependence from the steam consumption. To attain this purpose various means known in the art may be employed. For instance pump 13 as shown in Fig. 1 is driven by an electric motor 14 which is controlled by a rheostat 15 in any suitable manner. The rheostat arm 15 is connected with the pressureresponsive element 5 connected to a steam main 2 by means of the pipe 5 and consisting of a piston balanced against the steam pressure by a spring 5. \Vhen the steam pressure varies in main 2 the piston is shifted and accordingly operates rheostat 15 and thus controls the motor and thereby the output of pump 13. The pump 23 is automatirall v regulated from a thermo-rcgulator 6 which is responsive to the temperature behind the economizer at. Thermo-rcg ulator 6 which may be of any conventional type operates the' arm '25 of rheostat 25' which in turn controls the motor 24 which operates pump 23 and thereby controls the output of the latter. The construction of the thermostat 6 is not shown here in detail. as it may have any of the well known forms'suitable for this purpose. The sumption for the present operation is. that the economizer a proximatel the thermostat, on responding to a rise in temperature due-to decrease in water volume, moves rheosta-t arm to cut out resistance in order to increase the motor and pump speed.

Since the water must be passed through uniformly and the boiler is directly fed y the pump 13 only or for the larger part during periods of low steam consumption, the water supplied by the economizer 4 can during these periods not be fed into the boiler. It is therefore stored in the hot water storage vessel 8 until required. It is fed, into the boiler by the pump 33 when there is great demand for steam. The pump 33 is prefer ably regulated in dependence from the steam pressure in the pipe 2. Pump 33 for this purpose is driven by an electric motor 34 controlled thru a rheostat whose operating arm 35 is controlled by a pressure responsive element 9 connected'to the steam main 2 and of a t pe similar to element 5 previously referred to, so that theoutput of pump 33 can be varied in accordance with the varying steam pressure in main 2. During perlods of great steam demand the pump 13 thus supplies no feed water or small quantities only while the pump 33 supplies large quantities.

If during periods of low steam consumption in spite of increased feeding with cold water, for instance in spite of feeding by the pump 13 only, excessively large quantities of steam are produced so that for instance the pressure in the pipe 2 rises heated boiler water overflows from boiler 1 into the storage vessel 8 through the pipe 10, and thus supplies this vessel with hot water hesides the water heated in the economizer 4. The hot water thus discharged from the boiler is as a matter of course replaced by cold water raised by the pump 13. In this manner the water in the boiler is cooled and the steam generation drops and the store of hot water in the vessel 8 increases.

The exchange between the stored hot water and the boiler water is regulated as stated before by the pump 33 in dependence from the steam pressure in the pipe 2. The pump 33 may however work continuously and the regulation of the exchange between. the stored hot water and the boiler water can equally well be regulated only by the pump 13 which feeds more or less cold water into the boiler according to the demand for steam and which, on overfeeding of the boiler with cold water, forces hot waterinto the hot water storage vessel 8 through the'pipe 10. The continuous operation of pump 33 is shown in Fig. 2, its motor 34 being directly connected to the current supply.

The system of boiler feeding according to my invention has the essential advantage that with extremely simple and small means an adaptation of the steam generation to the steam demand can be attained at permanently uniform firing in boiler lants provided with feed water heating by t e flue or waste gas.

What I claim as my invention and desire to secure by Letters Patent is 1. In a steam boiler plant the combination of a boiler, a waste gas water heater, means for feeding the boiler with cold water, means for feeding the boiler with waste gas heated water, means for substantially continually feeding cold water through said water heater, means for storing the heated water and means responsive to load variations of the boiler for controlling the ratio between the amount of heated and cold water, to .be fed int? the boiler, in dependence from the boiler 2. In a steam boiler plant the combination of a boiler, a feed water reservoir, a feed water conduit between the boiler and said reservoir, :1 feed pump in said conduit, means for automatically controlling the output of,

said pump in dependence of'the live steam pressure 11 the boiler, a waste gas water eater, conduits between said heater and said reservoir and said boiler, a feed pump in the conduit between the reservoir and said heater and means for controlling the output of said last named pump in dependence of the feed water temperature behind said heater.

3. In a steam boiler plant the combination of a boiler, a feed water reservoir, a feed Water conduit between the boiler and said reservoir, a feed pump in said conduit, means for automatically controlling the output of said pump in dependence of the live steam pressure'in the boiler, a waste gas water heater, conduits between said heater and said reservoir and said boiler, a feed pump in the conduit between the reservoir and said heater and means for controlling the output of said last named pump in dependence of the feed water temperature behind said heater and a hot water storage vessel connected between the boiler and the heater adapted to store the excess amount of feed water delivered by said heater.

4. In a steam boiler plant the combination of a boiler, a feed water reservoir, a feed water conduit between the boiler and said reservoir, a feed pump in said conduit, means for automatically controlling the output of said pump in de endence of the live steam pressure in the oiler,- a waste gas water heater, conduits between said heater and said reservoir and said boiler, a feed pump in the conduit between the reservoir and said heater and means for controlling the output of said last named pump in degendence of the feed water temperature belnd said heater, a hot water storage vessel connected between the boiler and the heater 'water delivered by said heater, and a hot 7 feed water pump connected at its delivery side to said boiler and at its suction side between said storage vessel and said heater.

5. In a steam boiler plant the combination of a boiler, a feed water reservoir, a feed water conduit between the boiler and said reservoir, a feed pump in said conduit, means for au matically controlling the output of said pu p in dependence of the live steam pressur in the boiler, a waste gas water heater, conduits between said heater and said reservoir and said boiler, a feed pump in the conduit between the reservoir and said heater and means foricontrolling the'output of said last named pump in dependence of the feed water temperature behind said heater, a hot water storage vessel connected between the boilertand the heater adapted to store the excess amount of feed water delivered by said heater, a hot feed water pump connected at its delivery side to said boiler and at its suction side between said storage vessel and said heater,

and means for controlling the output of said hot feed water pump. 7

6. In a steam boiler plant the combination of a boiler, a feed water reservoir, a feed water conduit between the boiler, and said reservoir, a feed pump in said conduit, means for automatically controlling the out-. put of said pump in dependence of the live steam pressure in the boiler, a waste gas Water heater, conduits between said heater and said reservoir and said boiler, a feed pump in the conduit between the reservoir and said heater and means for controlling the output of said last named pump in dependence of the feed water temperature be-.

hind said heater, a hot water storage vessel connected between the boiler and the heater adapted to store the excess amount of feed water delivered by said heater, a hotfeed water pump connected at its delivery side to said boiler and at its suction side between said storage vessel and said heater, and means for controlling the output of said hot feed water pump automatically in ldependence ofthelive steam pressure in said oiler.

7. In a steam boiler plant the combination of a boiler, a feed water reservoir, a

feed water conduit between theboiler and said reservoir, a feed pump in said conduit, means for automatically controlling the output of said pump in dependence of the live steam pressure in the boiler, a waste gas water heater, conduits between said heater and said reservoir and said boiler, a feed pump in the conduit between the reservoir and said heater and means for controlling the output of said last named pump in dependence of the feed water temperature behind said heater, a. hot water storage vessel connected between the boiler and the heater I adapted to store the excess amount of feed water delivered by said heater, a hot feed water pump connected at its delivery side to said boiler and at its suction side between said storage vessel and said heater, means for controlling the output of said hot feed water pump automatically in dependence of the live steam pressure in said boiler, and means for conveying any excess of hot water from the boiler to said storage vessel.

8. In a steam boiler plant the combination of a boiler, a feed water reservoir, a feed water conduit between the boiler and said reservoir, a feed pump in said conduit,

means for automatically controlling the output of said pump in dependence of the live steam pressure in the boiler, a waste gas water heater, conduits between said heater and said reservoir and said boiler, a feed pump in the conduit between the reservoir and said heater and means for controlling the output of said last named pump in dependence of the feed water temperature behind said heater, a hot water storage vessel connected between the boiler and the heater adapted to store the excess amount of feed water delivered by said heater, a hot feed water pump connected at its delive side to said boiler and at its suction si e between said storage vessel and said heater,

'means for vcontrolling the output of said 

